This product is either discontinued or we cannot get that from suppliers.
Cisco Catalyst WS-C3850-12XS-S, Port 12 x 10 Gigabit Ethernet Expansion Slot, Optical Fiber, 10 Gigabit Ethernet, Network 10GBase-X, Expansion Slots-12, SFP+ Slots-12, Rack-mountable.
WS-C3850-12XS-S switch provides 12 ports 10Gbps SFP+ connection with upgradeable IP base image and build in wireless controller provide fully convergence between wired and wireless on a single platform.